Persons who play baseball, softball, and similar sports, often use various devices and methods to improve their batting skills. For example, players may utilize a plurality of bats, a single bat with weighted collars or clamps and the like attached thereto, permanently weighted bats (e.g. hollowed out bats with solid or flowable weight materials included therewithin), or a bat with attached vanes or the like to effect aerodynamic drag. Such devices and methods are employed to facilitate general warming-up, stretching muscles, and developing the muscles used for batting, as well as to improve a player's bat speed, reaction skill, bat control, and the like. Swinging a plurality of bats can be awkward, and there is a limit as to how many bats a person can swing safely and/or comfortably.
A weighted collar for a ball bat is disclosed in U.S. Pat. No. 3,521,883, which issued to F. Hamilton on Nov. 27, 1967. The Hamilton collar comprises a rigid ring-like member adapted to slide over the handle of a bat and create an interference fit with the larger end thereof. Centrifugal force acts to hold the ring-like member in place as the bat is swung. A more complex collar is disclosed in U.S. Pat. No. 4,260,150, which issued to M. Tabet on Aug. 17, 1979. The Tabet collar comprises a resilient member disposed between two rigid members. The two rigid members serve to provide the weight to the device and to encapsulate the resilient member which serves to frictionally engage the bat. Such devices have, however, been found to be unsafe as they can become dislodged during swinging. Additionally, these devices are not adjustable because the position of the collar on the bat is generally predetermined by the interference of the inside diameter of the collar with the outside diameter of the barrel of the bat.
A weighted clamp for a bat is also disclosed in U.S. Pat. No. 3,834,697, which issued to J. McNamara on May 14, 1973. The McNamara device is similar in principle to the Hamilton and Tabet collars (e.g. supplemental weight added to a bat), however, the McNamara device is attached by clamping action instead of simple interference fit. Additionally, while its position along the bat is adjustable, the McNamara weighted clamp can also become dislodged during swinging.
A fixed or permanently weighted bat is disclosed in U.S. Pat. No. 3,246,894, which issued to L. Bratt on Mar. 11, 1974. The Bratt device includes sand ballast contained within the upper portion of its barrel. In order to change the weight of the Bratt bat, one must disassemble the barrel portion of the bat and add or remove sand or other flowable ballast.
Training devices that include vanes or the like to effect aerodynamic drag during swinging exercises are disclosed in U.S Pat. No. 3,809,397, which issued to B. Gruenewald on Apr. 3, 1972, and U.S. Pat. No. 4,330,121, which issued to J. McCafferty on Oct. 2, 1980. With such devices attached to the barrel of the bat, the batter experiences a resistance to the swinging motion as the vanes "push" through the air. The amount of resistance experienced by the batter is proportional to the angular velocity with which the bat is moved. Therefore, a batter must swing the bat faster to simulate additional bat weight, a requirement not always compatible with effective training or warm-up procedures.
As described above, despite all of the prior work done in this area, there remain problems of safety, adjustability, and convenience in incorporating weighted devices into training devices.